| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 4 |
0.4%
|
| -7 | Does not apply | 4 |
0.4%
|
| 0 | No obstacle | 226 |
22%
|
| 1 | Minor obstacle | 185 |
18%
|
| 2 | Moderate obstacle | 201 |
19.6%
|
| 3 | Major obstacle | 296 |
28.9%
|
| 4 | Very severe obstacle | 109 |
10.6%
|